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Ferromagnetic half levitation of LK-99-like synthetic samples

arxiv.org

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Re: Ferromagnetic half levitation of LK-99-like synthetic samples

#11

Post by VHRanger »

carabiner wrote: post #9
VHRanger wrote: post #4

After reading the r/physics thread on LK-99 [1] I've cooled significantly on the matter. Basically: people who work in SC think the initial science seems very sloppy and the replication attempts don't come close to what you need to demonstrate a RT SC [1] https://www.reddit.com/r/Physics/comments/15i3h9d/lk99_megat...

People were saying the initial papers were trash in the first day of their release over a week ago, so that's ancient history and immaterial now. Same with the "replications," they're obviously insufficient when they're generating pieces the size of a pin head that can't be attached to probes. All of us are in a holding pattern waiting for some big lab like Argonne to confirm or deny its SC status.

How would you *deny* the SC status?

Replications keep failing until everyone is pretty sure it's not it. Proving the absence of something is rare to see.

Re: Ferromagnetic half levitation of LK-99-like synthetic samples

#12

Post by XorNot »

freeone3000 wrote: post #3

So a completely different compound in a completely different shape.

Different but reproducing the only real current "signature" LK99 behavior anyone's been able to show.

That a definitely non-superconducting material can do something similar is bad news for LK99.

Re: Ferromagnetic half levitation of LK-99-like synthetic samples

#13

Post by GuB-42 »

freeone3000 wrote: post #3

So a completely different compound in a completely different shape.

Yes, but I take it like a rebuttal.

They got the same effect that got everyone excited (half levitation) with a similar material that is ferromagnetic.

Considering that there is a lot of unknowns and randomness regarding the synthesis of LK-99, and that the half levitation effect can be explained by ferromagnetism, to me, it sounds much more likely that the original LK-99 is a ferromagnet rather than a superconductor. Simply because ferromagnets are common, and a room temperature superconductor is an extraordinary claim.

I'd like to be wrong, but for now, it doesn't look good for superconductivity.

Re: Ferromagnetic half levitation of LK-99-like synthetic samples

#15

Post by jacquesm »

arpowers wrote: post #7

My main concern: Where are the original authors and why are they not helping people synthesize the replications?

That's a good question and there is a lot of speculation about that but ultimately we just do not know. There is a whole tree that you can set up to track their reasons, the big branch at the beginning is labeled 'it doesn't work' (which obviously is a bit short on the confirming side, it may still have a 'fraud' and a 'true believers' branch but that's academic) and then from the other branch you get branches which may be labeled as 'they don't know how they did it' and so on.

Re: Ferromagnetic half levitation of LK-99-like synthetic samples

#16

Post by tamimio »

versteegen wrote: post #10
m3kw9 wrote: post #8

Has anyone even seen a ferromagnet stand up like that in a magnetic field?

Yes. https://nitter.net/VanGennepD/status/1688052003216261120 And this new paper finally rigorously explains away all the half-levitation videos. They can no longer be considered any evidence of SC at all.

Lol, so it was all super glue and iron!?

Re: Ferromagnetic half levitation of LK-99-like synthetic samples

#18

Post by ycui1986 »

xqcgrek2 wrote: post #6
freeone3000 wrote: post #3

So a completely different compound in a completely different shape.

The XRDs are nearly identical. It's a dead horse.

XRD used here only shows crystal lattice information for random orientated polycrystalline. It does not mean the two samples are identical. It does not prove whether they had single crystal or polycrystal.

You will need a four-circle diffractometer to prove two samples are identical, that also only work on single crystal if anyone can make it.

Re: Ferromagnetic half levitation of LK-99-like synthetic samples

#19

Post by disconcision »

marginalia_nu wrote: post #14
m3kw9 wrote: post #8

Has anyone even seen a ferromagnet stand up like that in a magnetic field?

We've levitated a living frog in a magnetic field. Starting to remind me of the logic of the witch test in monty python and the holy grail.

If LK-99 has the same resistance as the weight of a levitating frog, it's a superconductor

Re: Ferromagnetic half levitation of LK-99-like synthetic samples

#20

Post by throwawaymaths »

versteegen wrote: post #10
m3kw9 wrote: post #8

Has anyone even seen a ferromagnet stand up like that in a magnetic field?

Yes. https://nitter.net/VanGennepD/status/1688052003216261120 And this new paper finally rigorously explains away all the half-levitation videos. They can no longer be considered any evidence of SC at all.

For the half levitated ferromagnetic sample: isn't there torsional force where that disc touches the magnet?

At this point we have many examples where it's fully levitated.

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